This invention relates generally to packaging systems, and more particularly to flexible gusseted packages having an openable and reclosable interlocking seal provided with snap detents spaced along a major part of the length of the seal, the reclosable interlocking seal having male and female parts with the detents being formed in the female part and extending into the male part. The novel seal and snap detents structure provides tactile and auditory snap indications of the state of the seal during opening and closing of the package. Disclosed are methods and apparatus for making such packages and seals from a continuous web of flexible film, the seals being formed during package formation at line speed.
The advantages of gusseted packages for the storage of some kinds of substances is well known, and particularly where a wide mouth package or pour spout is desired. They also provide superior case packing and display shelf utilization as compared to stand-up pouches which may have zipper closures. The known art directed toward gusseted packages with some form of snap closure is Galomb U.S. Pat. No. 6,082,897. Galomb discloses a bulky two element pre-formed semi-rigid snap structure comprising a male part and a female part both affixed to the outside of the package by tacking or adhesive, each of which parts is secured to the package material along only one of the part edges so that the package material can move longitudinally relatively to the female part and can be stuffed into it by the male part during package closure. The snap parts are sufficiently bulky and rigid that they are not capable of being run over the forming collar of a vertical form fill apparatus and must be separately inventoried and affixed to the package after it has been formed. No apparatus for or method of making the package is disclosed by Galomb.
The method and apparatus for making the gusseted package according to the present invention utilize novel composite packaging film structures comprising the packaging film with several different configurations of strips of formable plastic laminated to the film at package length intervals from which several different gusseted packages are respectively formed, some packages having the formable plastic strip within the gussets and some packages which utilize relatively thick packaging film having the gussets formed without such plastic strip. The composite packaging film structures may be preformed and stored as roll stock material, which does not appear to be practical with the Galomb structure, or may be concurrently made with package formation by a Sig Pack, Inc. Easy Snap(trademark) Laminator mounted atop or adjacent to the packaging apparatus to form one of the shown and to be described specific novel composite packaging film structures, which composite film is then fed into the packaging apparatus with the plastic strips disposed on the inside of the package and incorporated into the novel reclosable seal formed in the film and strip composite. The laminator functions with both horizontal and vertical form/fill/seal wrapping machines and with over wrap packagers, and laminates various plastic strip materials to diverse heat seal packaging films to selectively form several related types of gusseted packages.
As disclosed in co-pending application 09/693,963, now U.S. Pat. No. 6,371,644, the packaging films could be for example, polypropylene, polyethylene, polystyrene, polyvinylchloride, thermoplastic heat seal coated non-plastic films, and various film laminations of two to four layers, while the plastic strip could be formed of one to three layers. In some applications the strip could be a single thickness of polyvinylchloride (PVC) heat sealed to a PVC film at a temperature of about 230xc2x0 F. for xc2xd to xc2xe seconds, while in other applications the strip could be of two layers such as PVC plus a sealing layer, or three layers such as a center layer coated on opposite sides respectively with a sealing layer and a release layer to prevent the strip from self adhering during formation of the reclosable interlock seal. A commonly used packaging film is a four layer film consisting of two layers of polypropylene separated by a layer of low density polyethylene and having a heat seal layer of low density polyethylene coated on one face.
The invention is shown and described in conjunction with a modified vertical form, fill and seal packaging machine having a novel package sealing press which latter also forms the novel resealable closure, the packaging machine being for example a Sig Pack, Inc. Eagle Infinity, Model 1524 fitted with standard gusset tooling.
Gusseted packages made according to the invention incorporating the novel reclosable seal also address consumer complaints relating to prior art zipper seals by providing clear auditory and tactile indications of the closing of the reclosable seal by incorporation of snap detents, so that the consumer is assured that the package has been resealed even in the absence of visual package inspection.
Accordingly, it is a primary object of the invention to provide novel methods and apparatus for making gusseted packages with openable and reclosable interlocking seals.
An additional object of the invention is to provide novel methods and apparatus for making gusseted packages having a novel openable and reclosable interlocking seal as aforesaid in which the bulk of the seal structure is provided by an added layer of strip material secured in a specific way to the packaging film at package length intervals.
A further object of the invention is to provide novel methods and apparatus for making gusseted packages having novel openable and reclosable interlocking seals as aforesaid in which the ends of the strip material are positioned in abutment at substantially the center of one face of the package to provide a hinge to assist in package opening.
Still another object of the invention is to provide novel methods and apparatus for making gusseted packages having reclosable interlocking package seals having male and female parts with snap detents formed in the parts, the closure structure providing tactile and auditory snap indications of the state of the closure during opening and closing of the package.
A yet further object of the invention is to provide novel methods and apparatus for making gusseted packages as aforesaid in which the reclosable interlocking seal is formed from the packaging film and a heat sealable strip heat sealed to the packaging film.
A still further object of the invention is to provide novel methods and apparatus for making gusseted packages as aforesaid in which the packages may be formed from a variety of packaging films such as polypropylene, polyethylene, polystyrene, polyvinylchloride, and various film laminates.